Question

While trying to make a Audio Player , currently working at Playlist ,and i have problem’s with shuffle function .

First i have a list with file names within:

List<string> myPlaylist = new List<string>();
            myPlaylist.Add("Untitled1.mp3");
            myPlaylist.Add("Untitled2.mp3");
            myPlaylist.Add("Untitled3.mp3");

and than with this method im getting random item at playlist :

public string shuffleme(List<string> playlist)
        { 
            Random random = new Random();
            int playlistitem = random.Next(0,playlist.Count);
            return playlist[playlistitem];
        }

but i need to get random element based in some kind of probability ,let say i have 1-10 values which describes a Playlist Item priority so the Item with the Lowest Priority will have a better chance to be returned against the Item with the Higher priority ,so i need to get Random item with probability based on item priority .

Answer 1

What you can do is create a playlist in the following way:

• Every high-priority item, place it 3x in the list.
• Every mid-priority item, place it 2x in the list.
• All other items, place them 1x in the list.
• Shuffle the list.
• Verify that no song appears twice in a row; if you find one that does (say, at locations 11 and 12), simply swap the second one with the next one in the list (i.e., as in this example, swap #12 with #13).

Then when it is time to select the next song, just pick the first one in the list, take it out and place it back in a random location in the 2nd half of the list.

That should do the trick!